The Costa Concordia and other cruise ships owned by the same company were hotbeds of sexual harassment, drinking and drug abuse, former crew members have claimed.

Two female ex-crew members have reportedly told Italian prosecutors leading the investigation into the sinking of the Concordia off an Italian island six weeks ago that they saw officers snorting cocaine, drinking to the point of inebriation and harassing female staff.

Capt Francesco Schettino, the commander of the 950ft-long vessel, "used women as goods to be exchanged," one of the women said, according to two Italian dailies, La Stampa and Il Messagero.

The two ex-crew members, one a nurse and the other a passenger rep, worked on the Costa Concordia and other ships owned by Costa Cruises in 2009 and 2010.

Their claims are reportedly contained in 5,000 pages of evidence gathered by prosecutors in Grosseto, Tuscany, where the investigation into the Jan 13 disaster is based.

The nurse, identified only as Valentina B., said she worked with Capt Schettino on the Costa Atlantica, another ship in the fleet, in January and February 2010 but had resigned because she had encountered "corruption, drugs and prostitution".

"I saw with my own eyes officers taking cocaine – to prove it you would only have had to test them," she reportedly told investigators.

She said she had worked on three Costa Cruises vessels, "each one worse than the other".

The second woman, identified as Mary G., told prosecutors in Grosseto: "I worked on the Costa Concordia in 2010 for two months. Very often the officers and other members of the crew were drunk. Often we'd say to ourselves, 'If there's an emergency, who's going to save the ship?'"

She claimed to have been "molested" by a crew member who was high on drugs.

Costa Cruises did not respond to the specific allegations but said there were "strict regulations" on all its ships against the use of illegal drugs, with regular checks carried out.

"We operate strict safety and surveillance measures concerning drugs possession on board our ships," a statement said. "The possession or trade of narcotics on board is prohibited. Crew members who possess or use drugs or engage in drug trafficking are submitted to disciplinary provisions and disembarked. On board there are checks and preventive actions to discourage such behaviours.

"Costa crew are not allowed to consume alcohol in a quantity that may impair the capacity to perform on-board duties. In addition, the crew on guard must abstain from the use of alcoholic beverages at least 4 hours before the start of their shift."

The first pretrial hearing into the capsizing of the Concordia will be held on Saturday in Grosseto.

The confirmed death toll from the disaster is 25, with another seven people still missing, presumed dead.